How would you call this Void return type function as a method using its given arguments?-CodePudding

This feels like a simple error that I'm just not understanding. I'm trying to call my downloadImage() function on cell.profileImageView (UIImageView) yet I'm receiving an error stating:

Cannot convert value of type '(status: Bool, image: UIImageView?)' to expected argument type '((status: Bool, image: UIImageView?)) -> Void'

How do call the downloadImage() as a method for cell.profileImageView.downloadImage()? The downloadImage() function and and tableView() function containing where the error occurs are below:

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "EmployeeTableViewCell", for: indexPath) as! EmployeeTableViewCell
        let employeeData = viewModel.employees[indexPath.row]
        cell.nameLabel.text = employeeData.fullName
        cell.teamLabel.text = employeeData.teamName   " Team"
        cell.emailLabel.text = employeeData.emailAddress
//        if employeeData.smallPhotoUrl != nil {
//            cell.profileImageView.(urlString: employeeData.smallPhotoUrl!)
//        }
//        cell.profileImageView.downloadImage(URLString: employeeData.smallPhotoUrl)
        cell.profileImageView!.downloadImage(from: employeeData.smallPhotoUrl!, with: ((status: true, image: cell.profileImageView!)))
        
        return cell
    }

func downloadImage(from URLString: String, with completionHandler: @escaping (_ response: (status: Bool, image: UIImageView? ) ) -> Void) {
        guard let url = URL(string: URLString) else {
            completionHandler((status: false, image: nil))
            return
        }
        
        URLSession.shared.dataTask(with: url) { data, response, error in
            guard error == nil else {
                completionHandler((status: false, image: nil))
                return
            }
            
            guard let httpURLResponse = response as? HTTPURLResponse,
                  httpURLResponse.statusCode == 200,
                  let data = data else {
                completionHandler((status: false, image: nil))
                return
            }
            
            let image = UIImageView()
            completionHandler((status: true, image: image))
        }.resume()
    }
}

CodePudding user response：

First of all a completion handler is not used for passing data to the method. It's used for retrieving data from a method call after it completes it's work. So you either need to call it as:

cell.profileImageView!.downloadImage(
   from: employeeData.smallPhotoUrl!, 
   with: { status, image in
      /// Do what you want with the status or the image values
})

For example when you call completionHandler((status: false, image: nil)) from the downloadImage method the status will be false and image will be nil in the above code.

From what I understand you don't need a completion handler here. You just need a method to set the image to the image view. So changing the implementation to this might work for you:

func downloadImage(from URLString: String, to imageView: UIImageView) {
   /// Download the image as you do and once you get the data value
   imageView.image = UIImage(data: data)
}

Then you can download the image and set it like this:

cell.downloadImage(from: employeeData.smallPhotoUrl!, to: cell.profileImageView!)